Code or workaround to create snap to pixels from unwrap
I'm not a massive user of this feature, but as far as I can tell, Snap to Pixels refers to snapping while you are moving UVs around in the editor using the standard translation tools, like G, R and S. See the comparison in this GIF (first I move around without Snap to Pixels enabled, then with):



The trick is, you simply enable the G tool, and the vertices will already snap. Just LMB click to confirm.